Enhancing the performance of a solar distiller using phase change materials integrated with Peltier modules and Heaters: Energy, exergy, and economic analysis

Abstract

• The performance of solar still using PCM , Peltier and heaters was investigated. • The percentage increase in productivity was 131.8% for the modified solar still. • The thermal and exergy efficiencies for the MSS were 73.5% and 5.8%, respectively. • The cost per liter of the modified solar still was $0.008 at a water depth of 1 cm. Solar stills provide a sustainable solution to freshwater scarcity by utilizing solar energy to purify water, making them an environmentally friendly option in the context of climate change. This study presents an experimental investigation into the performance of a solar still enhanced with phase change materials (paraffin wax), Peltier modules, and electric heaters powered by a photovoltaic system. Two identical single-slope solar stills were constructed using the same materials and dimensions: one as a conventional solar still (CSS) and the other as a modified solar still (MSS). Key parameters, including temperatures, solar radiation, and water productivity, were measured and recorded hourly at Faculty of Engineering, Suez Canal University. Energy, exergy, and economic evaluations of both systems were conducted at water depths of 1, 2, and 3 cm. The results showed that the conventional and modified solar stills produced 3.58 and 8.30 l/m 2 ·day, respectively, indicating a 131.8 % increase in productivity for the modified still. In addition, the modified still also demonstrated higher energy efficiency, achieving 70 % compared to 47 % for the conventional one at a 1 cm water depth. At 3 cm, energy efficiency declined to 50 % for the modified solar still and 30 % for the conventional one. The average exergy efficiency of the MSS reached 5.8 %, compared to 3.5 % for the CSS at a 1 cm depth. The maximum thermal efficiency recorded was approximately 73.5 % for the MSS and 32.45 % for the CSS. Economically, the MSS produced 2975 L annually, compared to 1225 L for the CSS, resulting in a lower cost per liter of $0.008 versus $0.009. These findings demonstrate that integrating Peltier modules and phase change materials significantly enhances solar still performance, offering a cost-effective and sustainable solution for freshwater production.